Process for softening paper



Patented Jan. 6, 1942 QMTENT OFFICE mam i f lBOGESSFOKJSOHENING AP R Murray linoth, BrooklymNQY; assignor to The fmchardslflhcmical Works, Incorporated, Jer- 'sey' City, N. 1., orporation ol' New'Jersey j Application September seria1:No."za4,-135

' eams. (choc-287i My invention refers to a process for softening Another object of myinvention is to producea very soft and pliable paper, which does not, even at high humidities, acquire-.asoggy and clammyifeel 'dueito excessive absorption of .mois- :ture.

A further object of invention isto devise i i a process-for softening paper in which practically:no part oi the softening .agent is lost because of evaporation.

Still further. :objects are to provide a paper softeningprocess which-canbe 'carried outeasily and with a softening agent having a low and stable price.

I accomplish :these :andother objects which will become apparent asthe description proceeds, by:treatingxthe .paperwith anaqueous solutionoi .unreacted urea-whichxis applied to thepaper web bymeans oi asize press,spray, kiss roll,.or any other .means for uniformly impregnating the paper. While it is-:most convenient to apply the aqueous solution to the dry .paper web, this .is not strictly-necessarypand, if desired, the plasticizer may b applied :to a even to a wet web. I

In mixture withthe aqueous solution of unreacted urea, there :may beiused various hygroscopicsubstances, such as glycerine, diethylene glycol, calcium chloride, magnesium chloride. zinc'chloridamagnesium sulfate; sodium acetate, sodium sulfate, sulfamic acid, ammonium sultamate, sorbitol, mannitol, ammonium acetate,

tetra sodium pyrophosphate, tetrapotassium pyrophosphate, ethyl pyrophosphate, glucose, corn syrup,.dextrose, and invert sugar Fillers and surface modifiers, such as talc,

china clay, lbarytes, .blanc .flxe, titanium dioxide and other mineral fillers, may be used with the aqueous solution of unreacted .urea.

According to aspec'ific embodiment of my invention, Iuse'inmixture with the solution of 'unreacted urea, which may also contain a hygro-a scopic substance .and a filler, a suitable wetting and penetrating agent.. I have .i'ound that the wetting-outand penetration of the paper :by the solution is .particularlyquickened, the dispersion oi. the mineral fillers and opac'iflers such as .talc or china clay is improved, and a-surface lubricity enhancing-the softening effect is imparted to the. fibres, by :the presence in the aqueous solution partially dried web or of anionic or cationic surface active agents having thegeneral formula.

where it is an alkyl group, an aralkyl group, an'

alkaryl group, or a heterocyclic ring containing at least one nitrogen, carbon, oxygen, sulphur, or

phosphorus atom,

having the same meaning as R, and at least one of the R groups containing a straight carbon chain of at least 10 carbon atoms.

It is understood that instead of the amines mentioned their salts may be employed.

Anionic active agents of this type are for instance the following: sodium cetyl sulfate, ammonium lauryl sulfate. the sodium salt of sulionated stearyl alcohol, and the sulionation product of amyl substituted naphthalene or its salts.

Cationic active agents of the type described are for'instance the following:

Octadecyltrimethyl-ammonium sulfo-methylate, dimethyloctadecylamino hydrochloride, N- hydroxymethylpyridinium chloride, the hydrochloride of diethyl aminoethyloctadecyl carbonate, pentadecyldihydroimidazole hydrochloride, oleyl diethylenetriamine acetate, and diethyl sulfate quaternary of p diethylamino ethyl stearamide.

The following examples are intended to explain to the disclosures made therein. All the quan- 40 titles and percentages mentioned in the examples are by weight.

Example 1 A high wet strength creped sulfite paper web is passed through a bath consisting of an aque- Example 2 A stock solution is made up containing 40. per .cent unreacted urea, 20 per cent glycerine and 40 per cent water. parts of this solution, 10

the nature of the invention without limiting it ous solution containing 20 per cent of unreacted' parts talc. and 40 parts water are mixed thoroughly and put in the size press. The 'paper, which may be creped or uncreped; is passed through the size press at such a rate that it picks up an equal weightot solution whereupon it is dried as in Example 1. l

Example 3 A stock solution containing 40 'per cent urea, 20 per cent glycerine, 3 percent or a cationic surface active agent and 37'per cent water is made up. 55 parts of this stock solution; 10 parts talc and 35 parts oi. water are mixed together and used as the bath in the size press. The paper is treated in a manner similar to that used in Example 1.

Example 4 A stock solution containing 40 per cent urea, per cent glycerine, 10 per cent calcium chloride,

and 35 per cent water is made up. n 50- parts of 9 parts of the stock solution from Example :5,

1' part glycerine, 35.-part s in'yert sugarsolutiom and 55 parts water are mixed together andjadded to the size press used. in thefmanu'facturej o'f glassine. The 'squ'eez'eon the rolls and-the speed and glyee'rin'c only Iclaimz 1 aqueous solution o ntomiagzo z by weight of un this solution, 5 parts glycerine, 10 parts talc and- 35 parts water are intimately mixed and used asthe bath in the size press. The paperis passed throughin the usualmanner. Y 1 c Example 5 reacted-urea, 10% by weight .or glycerine, 19%

by we ghtj or talc'; andfioik, byweiahtoi water;- A softening ag'ent ioi paperucomprising an aqueoussolutioncontaining 20% by weight of un'-* react'ed'urea,12.5%;by weight of glyeerine,"5% I byweightof calcium chlori'de, 10% by I ",3; A-"soitenins. agent torpa'per; comprising-an A stock solution containing 40 per cent-urea,

' 20 per cent glycerine, 10- per cent calcium chlo ride, 2 per cent of a cationic-surface active agent and 28% water is made up, under heating ii. necessary. 50 parts of this solution, 10 parts talc, and 40 parts water are mixed and used in the size press for imparting cloth like'properties to creped high wet-strength paper.

aqueoussolution-containing, 20% by weight or, unreacted'urea, 10% by weightoi' glycerine,'5.%

by weight of calcium chloride, 1% by weight of a cationic surface active agent, 10% by. weight} of talc, and 54% by weightjofwater,

4, A softening agent for papercomprisin'g an,

aqueous solution containingirom about 3% to about"25% byweight of 'unreaotedureayfrom about 5% to' about" 18% by. weight of g lycerine' and about 10% hy'weightoliftalc. 4 j MURRAY-'H ROI' H.

i 1. A aotteningZagentFiorpapercomprising,

weight r" 

